Endogenous Retroviruses as Aging Clocks: HERV Reactivation as a Biomarker

Edisnap· Feb 24, 2026

This infographic illustrates how human endogenous retroviruses (HERV-K HML-2) become reactivated in aged cells due to weakened epigenetic silencing, leading to increased inflammation and cellular dysfunction, serving as a potential biomarker for 'epigenetic age'.

Human endogenous retroviruses (HERVs) comprise ~8% of our genome. Most are silenced by DNA methylation and histone modifications in somatic cells. But this silencing weakens with age.

HERV-K (HML-2), the most recently active family, shows increased expression in aged tissues. This has been dismissed as transcriptional noise or genomic instability.

Hypothesis: HERV reactivation is not merely a consequence of epigenetic drift but a functional component of the aging program—a readout of cellular "epigenetic age" that may also contribute to sterile inflammation and cellular dysfunction.